The present invention relates to an arrangement for the vibration-isolating mounting of an electric motor on a support part via an essentially disk-shaped support element, the support element having a motor-holding section for connection to the electric motor and a support-holding section for connection to the support part, and the two holding sections being connected via elastic, web-like connecting pieces.
Such a mounting for a motor is disclosed in DE-A 2 219 182. It is intended to be used to reduce tangential and radial vibration. In this, there is provided a support element, called a supporting member therein, which consists of an outer ring on the housing side, an inner ring which is connected to the motor and of essentially radial, elastic webs which connect the two rings in one piece. There is additionally provided a separate abutment in the form of a ring element which is placed axially onto the support element. The abutment part has stop webs having boundary surfaces in such a manner that, in interaction with limit stops provided on the inner ring of the support element, limiting of the tangential and radial vibrating movements of the motor is ensured. However, there is no provision for limiting movement axially. This known arrangement is only suitable for mounting relatively small, lightweight electric motors, such as are used, for example, in office machines.
German Patent 38 23 447 describes a fan which is operated by an electric motor and has a very similar mounting. To isolate noise, there is provided within a fan housing a disk-shaped component which is arranged transversely to the rotational axis of the fan, whose outer region is held on the inner surface of the housing, and to whose central region the fan, i.e. the motor with a fan wheel, is connected. In this case, the outer region is connected in one piece to the central region via a plurality of elastic webs. However, only an axial limiting stop is provided directly between the fan and the housing in this case, by the fan having two shoulders which point away from one another in the direction of the rotational axis of the fan and to which mating shoulders of the housing are assigned at a distance. The elastic webs have such a profile, for example, spiral or S-shaped, that their inner and outer attachment points on the central region and on the outer region are in each case offset with respect to one another in the circumferential direction by a certain angle .alpha.. This known arrangement is likewise only provided for relatively small fans, such as are used in motor vehicles for sensory detection of temperature in conjunction with the control of an air-conditioning system.
Finally, a further arrangement of this type is disclosed in German Utility Model 91 00 952. This also specifically concerns a sensory-operated cooling fan for use for controlling an air conditioning system in a motor vehicle. Moreover, in this case only an axial limiting stop is provided, specifically directly between a housing cover and the elastic webs of the support disk.
Proceeding from the described prior art, the present invention is based on the object of providing an arrangement of the generic type which ensures effective vibration isolation even in the case of relatively large and heavy electric motors, such as are used, for example in heating fans (burner fans).
According to the invention, this is achieved by connecting pieces designed such that the two holding sections are elastically movable relative to each other three-dimensionally in all directions in space, specifically axially, radially and tangentially, in each case over a certain movement play. The support element includes integrated stop means for three-dimensional limiting of the elastic relative movements of the holding sections. It is advantageous to form the stop means at least partially from elements of the holding sections. The elements are elastically deformable such that relative movements are elastically absorbed and are thereby retarded relatively gently. Hard knocks are thereby avoided.
Even in the case of large and heavy motors which, if appropriate, form a unit together with a driven part, for example a fan wheel, the refinement according to the invention makes it possible reliably to avoid direct impacts occurring between the motor parts and housing parts so that unbalanced displacements possibly resulting therefrom are also virtually eliminated. The stop means according to the invention are effective, on the one hand, in the operating state if, for example, relative movements occur because of sudden changes in rotational speed. On the other hand, effective safety during transport is also achieved, according to the invention, in that even in the case of abrupt movements of the entire particular apparatus, for example a fan, all relative movements are very gently intercepted via the novel stop means of the support element.
For the preferred use in the case of relatively large and heavy motors it is above all expedient to connect the two holding sections and the connecting pieces, as originally separate component parts, together in a suitable manner. The connecting pieces are preferably connected in the radial outer region of the support-holding section and in the radially inner region of the motor-holding section, specifically, in particular via non-positive- and/or positive-locking connections. In principle, however, a reversed arrangement of the connecting pieces can also be provided, i.e. they can be connected on the outside to the motor-holding section and on the inside to the support-holding section. Because the component parts are originally separate the advantageous possibility arises of producing the holding sections and the connecting pieces from different materials. It is particularly expedient to produce the holding sections from a certain plastic material and the connecting pieces in particular from metal (spring steel plate). As a result, particularly high masses and bearing pressures can be supported. Furthermore, simple exchange or simple selection of the connecting pieces, which are in each case of appropriately different design, enables rapid adaptation to different requirements in the particular application.
In a preferred application, the support element is arranged axially between the support part--formed in particular by an essentially planar housing wall of a fan--and the electric motor, the electric motor serving to drive a fan wheel. In this case, a motor shaft extends centrally through the support element and through an opening in the fan housing wall and within the fan housing is connected to the fan wheel. Consequently, in this case the support-holding section is connected, on its side which is axially remote from the electric motor, to the support part, while the motor-holding section is connected, on its side which is axially remote from the support part, to the electric motor. For this purpose, the two holding sections each have disk-shaped wall sections which are spaced apart axially from one another. The support element according to the invention is basically thus a double disk with the connecting pieces being arranged axially in between. The holding sections have, for this purpose, sections which extend axially radially inward and outward, overlap in the radial direction and between which the connecting pieces extend. In this manner, the holding sections in practice form a receiving housing which axially and radially surrounds the connecting pieces. In so doing, provision is made, to form the stop means, for the two holding sections to interlock in some regions radially or axially with a corresponding movement play.
Further advantageous features for refining the invention are contained in the subclaims and the following description.